Various carbon sources have been reported to be convertible to gases such as hydrocarbons by first converting these carbon sources to a carbon monoxide comprising gas. One process that has been processed for this purpose involves the reaction of the carbon source with zinc oxide, the separation of zinc from the carbon dioxide and a zinc-comprising gas produced, the reoxidation of the zinc to zinc oxide and the reintroduction thereof into the reaction with the carbon source. There is a general need for further improvements of this basic process, particularly since economical reasons constitute a dominating factor for success or failure of any gasification process. The recovery of zinc and the most complete use of the heat developed in the process thus are of utmost importance.